Medical apparatus

ABSTRACT

Medical apparatus 10 includes a barrel 12 which defines a chamber 14 therein. A sleeve 16 is slidably arranged on the barrel 12 between a first, retracted position and a second, extended position in which a needle of a needle assembly 48 is covered. A coil spring 20 is interposed between the barrel 12 and the sleeve 16 for urging the sleeve 16 to its second position. A locking means 18 locks the spring both in its first position and in its second position.

FIELD OF THE INVENTION

THIS INVENTION relates to medical apparatus. The invention relatesparticularly to medical apparatus for use in removing fluid from orinserting fluid into a body.

SUMMARY OF INVENTION

According to the invention, there is provided medical apparatus whichincludes

an elongate cylindrical member defining a chamber therein and having aformation at one end for mounting a needle assembly on the cylindricalmember;

a protective element slidably mounted relative to the cylindrical memberbetween a first, retracted position in which, in use, a needle of theneedle assembly is exposed and a second, operative position in which theneedle is covered; and

an urging means interposed between the cylindrical member and theprotective element for urging the protective element to its secondposition.

The cylindrical member may be in the form of a barrel partially closedat one end, said partially closed end defining the formation, and theprotective element may be in the form of a sleeve slidably ortelescopically mounted on the barrel. To ensure reliable operation ofthe apparatus, the barrel may be circular cylindrical having an outerdiameter which is only slightly less than that of an inner diameter ofthe sleeve, which may also be circular cylindrical, so that the sleeveand barrel can slide relative to each other and jamming is inhibited.

The apparatus may include a locking means for locking the sleeve atleast in its first position relative to the barrel. Preferably, thelocking means locks the sleeve in both its positions relative to thebarrel.

Still further, the apparatus may include a guide means for guidingmovement of the sleeve relative to the barrel.

The guide means may include guiding formations defined in the barrelwith guide elements, which co-operate with the guiding formations, beingcarried on the locking means.

The invention has particular application in apparatus used in collectingblood for analysis. Hence, an evacuated vial is removably insertableinto the chamber of the barrel for the collection of blood for analysispurposes. Thus, the needle assembly used is a double pointed,blood-collecting needle having a first needle projecting outwardly fromthe barrel with a second needle projecting into the chamber of thebarrel, in use, to pierce a membrane of the vial to cause blood to becharged into the vial. The needles may project in opposite directionsfrom a boss which is mounted on the formation of the barrel. The bossmay be screw-threaded and the formation of the barrel may have acorrespondingly screw-threaded passage defined therethrough.

The outer needle of the needle assembly is covered by a sheath when notin use. The sheath has a formation which engages the boss of the outerneedle. Thus, the free end of the sleeve may have an opening definedtherein in which said formation of the sheath is snugly received suchthat, when the sleeve is retracted from its second position to its firstposition, the sheath covers the outer needle and its formation isreceived over the boss. The sheath can then be used to unscrew the bossfrom the passage of the barrel.

The locking means may comprise a mounting means carried on the sleeveand a locking arrangement extending from the mounting means, the lockingarrangement having the guide elements. More particularly, the mountingmeans may comprise a collar carried on an outer surface of the sleeveand the locking arrangement may comprise a pair of opposed armsextending from the collar in a direction substantially parallel to alongitudinal axis of the sleeve. A free end of each arm may carry one ofthe guide elements thereon. The guiding formations of the barrel may bein the form of a pair of opposed, longitudinally extending slots definedin a peripheral wall of the barrel. Each slot may be substantiallydumbbell-shaped having a laterally enlarged region at each end.

Each guide element may comprise a clip which co-operates with itsassociated slot in the barrel and which engages said enlarged region ofthe slot, either when the sleeve is in its first position or in itssecond position relative to the barrel.

The arms of the locking means may be of a resiliently flexible material.Then, to release the clips from the enlarged regions, pressure isexerted on the arms to urge the clips into the interior of the barrel toeffect sliding displacement of the sleeve relative to the barrel. Hence,it will be appreciated that, when the sleeve is in its first positionand pressure is applied to the arms to release the clips from theenlarged regions of the slots, the spring bears against the sleeve andthe barrel to cause relative displacement of the barrel and the sleeveuntil the sleeve is in its second position. Then, releasing the armscauses the clips to be received in the other enlarged regions to lockthe sleeve in its second position relative to the barrel.

The urging means may comprise a spring. The spring may be a coil springwhich is substantially frusto-conical in its relaxed condition, anarrower end of the spring being mounted about the formation of thebarrel and a wider end of the spring bearing against a corresponding endof the sleeve.

The invention is now described by way of example with reference to theaccompanying diagrammatic drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings,

FIG. 1 shows a plan view of medical apparatus, in accordance with theinvention, together with components with which the apparatus is used andwith a protective element of the apparatus in a second position;

FIG. 2 shows on an enlarged scale, a sectional side view of the medicalapparatus with the protective element thereof in its first position; and

FIG. 3 shows a sectional end view of the apparatus taken through lineIII--III in FIG. 2.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to the drawings, medical apparatus, in accordance with theinvention, is illustrated and is designated generally by the referencenumeral 10.

The apparatus 10 comprises an elongate cylindrical member or barrel 12which defines a chamber 14 therein. A protective element in the form ofa sleeve 16 is slidably arranged on the barrel between a first positionas shown in FIG. 2 of the drawings and a second position as shown inFIG. 1 of the drawings. The apparatus 10 further includes a lockingmeans 18 carried on the sleeve 16 for locking the sleeve 16 both in itsfirst position and in its second position.

An urging means in the form of a coil spring 20 is interposed between anend 22 of the barrel 12 and a free end or nose portion 24 of the sleeve16. The spring 20 is substantially frusto-conical with its narrower endabutting against the end 22 of the barrel 12 and its wider end abuttingagainst the nose portion 24 of the sleeve 16. Hence, when the sleeve 16is in its second position relative to the barrel 12 the spring 20 iscompressed and, due to its frusto-conical construction, takes up lessspace than would otherwise be the case.

The apparatus 10 further includes a guide means 26 for guiding slidingmovement of the sleeve 16 relative to the barrel 12. The guide means 26is used in conjunction with the locking means 18.

The guide means 26 comprises a pair of opposed longitudinally extendingslots 28 defined in a wall 30 of the barrel 12. As illustrated moreclearly in FIG. 1 of the drawings, each slot 28 has an enlarged endregion 32 imparting a substantially dumbbell shape to the slot 28.

The locking means 18 includes a collar 34 mounted fast about an outersurface of the sleeve 16. The collar 34 has a pair of opposed arms 36extending therefrom in a direction parallel to the longitudinal axis ofthe sleeve 16 towards a distal end 16.1 of the sleeve 16. A free end 38of each arm 36 has a radially inwardly extending constricted portion 40(FIG. 3) with a laterally enlarged foot portion 42 being arranged at afree end of the constricted portion 40. The width of the constrictedportion 40 of the clip is such that it can pass with clearance throughits associated slot 28 and the lateral dimension of the enlarged footportion 42 of each clip 38 is such that it is a snug fit within eachenlarged region 32 of its associated slot 28.

It is to be noted that the sleeve 16, at its distal end 16.1, has a pairof opposed cutaway portions 41 which lie in register with the slots 28and one of the enlarged regions 32 of the guide means 26 when the sleeve16 is either in its first position or in its second position.

When the sleeve 16 is either in its first position or in its secondposition relative to the barrel 12, the arms 36 are splayed outwardlysuch that the foot portions 42 are received in the relevant enlargedregions 32 of the slots 28 to hold the sleeve 16 in its first positionor second position, as the case may be, relative to the barrel 12.

The barrel 12 has, at its end 22, a longitudinally extending formation44 which defines an internally screw-threaded passage 46. The apparatus10 is used with a needle assembly 48 (FIG. 1) which has a central boss50. The boss 50 has an externally screw-threaded portion 52 which isscrew-threadedly received in the passage 46 of the formation 44 of thebarrel 12. Further, a first, outer needle 54 extends from the boss 50and, when not in use, is covered by a sheath 56. A second, inner needle58 projects from the boss 50 in an opposite direction to that of theneedle 54.

In use, the sleeve 16 is retained in its second position as shown inFIG. 2. With the sheath 56 attached to the boss 50, the boss 50 of theneedle assembly 48 is screwed into the formation 44 of the barrel 12. Itis to be noted that the sheath 56 has a formation 60 which is a snug fitin an opening 62 defined in the nose portion 24 of the sleeve 16.

The sheath 54 is removed and the needle 54 is inserted into a person'svein. Once the necessary preparations have been effected, an evacuatedvial 64 is inserted into the chamber 14 of the barrel 12 and a membraneat the end 66 of the vial 64 is pierced by the inner needle 58. Due tothe evacuated condition of the vial 64 blood from the person is drawninto the vial 64. Once the required quantity of blood has been drawn,the apparatus 10 is removed by withdrawing the needle 54 from theperson's vein.

To prevent a user of the apparatus 10 pricking himself with the now-usedneedle 54 radially inward pressure is exerted on the arms 36 to urge thefoot portions 42 of the clips 38 out of engagement with the enlarged endregions 32 of the slots 28 closer to a distal end 12.1 of the barrel 12.When the foot portions 42 of the clips 38 are free of said regions 32 ofthe slots 28, the sleeve 16 is urged, under the action of the coilspring 20, in the direction of arrow 68 to the position as shown in FIG.1 of the drawings. The arms 36 are then released such that the footportions 42 are received within the enlarged end regions 32 of the slots28 closer to the end 22 of the barrel 12. Hence, the sleeve 16 is thenlocked in that position relative to the barrel 12.

Whilst the sleeve 16 is in this position, the sheath 56 is mounted onthe nose portion 24 of the sleeve 16 by inserting the formation 60 ofthe sheath 56 into the opening 62 in the nose portion 24 of the sleeve16. The sleeve 16 is then again retracted to the position shown in FIG.2 of the drawings whereupon the sheath 60 is received over the boss 50of the needle assembly 48. The formation 60 of the sheath 56 is a tightfit on the boss 50. For this purpose also, the boss 50 haslongitudinally extending vanes (not shown) arranged thereon which engagecorresponding ribs in the formation 60 of the sheath 56. The needleassembly 54 is then unscrewed from the barrel 12 for disposal. Thoseskilled in the art will appreciate that the needle 58 of the needleassembly 48 of the type described is covered by an elastomeric cover soas to inhibit a user pricking himself with the inner needle 58.

Hence, it is a particular advantage of the invention that medicalapparatus 10 is provided which will reduce the likelihood of users ofthe apparatus 10 accidentally pricking themselves with contaminatedneedles. Thus, the likelihood of the transmission of life-threateningdiseases is reduced.

It is claimed:
 1. Medical apparatus for use with a blood collectingdevice, the apparatus includingan elongate cylindrical member whichdefines a chamber in which the blood collecting device is receivable,the cylindrical member having a mounting formation at one end formounting a needle assembly on the cylindrical member; a protectiveelement slidably mounted relative to the cylindrical member between afirst, retracted position in which, in use, an external needle of theneedle assembly is exposed and a second, operative position in which theneedle is covered; an urging means interposed between the cylindricalmember and the protective element for urging the protective element toits second position; a locking means carried by the protective elementand which engages locking formations defined in cylindrical member forlocking the protective element both in its first position and in itssecond position relative to the cylindrical member, the locking meansbeing arranged on an external surface of the protective element to bemanipulated by a user and the locking means including a lockingarrangement which projects through the protective element and thecylindrical member, the locking arrangement having engaging portionswhich engage the locking formations of the cylindrical member when theprotective element is either in its first position or its secondposition relative to the cylindrical member such that, when pressure isexerted by an user on the locking means, said engaging portions of thelocking arrangements are disengaged from said locking formations and areurged into the chamber of the cylindrical member to permit relativemovement between the cylindrical member and the protective element; anda guide means for guiding movement of the protective element relative tothe cylindrical member, with the guide means including guidingformations defined in the cylindrical member with guide elements, whichco-operate with the guiding formations, being carried on the lockingmeans.
 2. The apparatus as claimed in claim 1, in which the lockingmeans includes a mounting means carried on the sleeve with the lockingarrangement extending from the mounting means.
 3. The apparatus asclaimed in claim 2, in which the mounting means comprises a collarcarried on an outer surface of the sleeve and the locking arrangementincludes a pair of arms extending from the collar.
 4. The apparatus asclaimed in claim 3, in which the guiding formations of the barrelcomprise a pair of spaced, longitudinally extending slots defined in aperipheral wall of the barrel, the locking formations being defined ateach end of each slot.
 5. The apparatus as claimed in claim 4, in whicheach guide element comprises a clip which co-operates with itsassociated slot in the barrel, the clip including said engaging portionswhich engage the locking formations, when the sleeve is either in itsfirst position or its second position relative to the barrel.
 6. Theapparatus as claimed in claim 5, inclusive in which the urging meanscomprises a spring.
 7. The apparatus as claimed in claim 6, in which thespring is a coil spring which is substantially frusto-conical in itsrelaxed condition, a narrower end of the spring being mounted about themounting formation of the barrel and a wider end of the spring bearingagainst the nose portion of the sleeve.
 8. The apparatus as claimed inclaim 1, in which the cylindrical member is in the form of a barrelwhich is partially closed at one end, said partially closed end definingthe mounting formation, and in which the protective element is in theform of a sleeve slidably mounted on the barrel.
 9. The apparatus asclaimed in claim 8, in which the sleeve has a nose portion against whichthe urging means bears, the nose portion having an opening definedtherein in which a covering element is received so that, when the sleeveis in its first position relative to the barrel, the covering elementsheathes the external needle to enable the needle assembly to be removedfrom the mounting formation of the cylindrical member.